Why is Blender much slower on Linux Mint than on Windows with an RTX 4080?

It may be worth testing a newer distribution instead of assuming the hardware is the problem. Linux Mint is aimed at stability and has an older desktop base, while Fedora, Ubuntu LTS, or Kubuntu LTS may provide a newer kernel, desktop stack, and NVIDIA integration. A live USB or separate installation is enough for a quick comparison; you do not need to replace your current system immediately.

First separate viewport responsiveness from actual render speed. If rendering is enabled in the viewport, the UI can become much heavier because the GPU is also busy rendering continuously. Try comparing the same scene in Solid or Material Preview mode, and test Blender’s Vulkan display option. For final rendering, OptiX is generally the right choice on an RTX 4080. Blender Open Data can also help determine whether the render performance itself is abnormal or whether the slowdown is mainly the desktop interface.

The desktop stack is worth investigating. Cinnamon on X11 can behave differently from Windows, especially with NVIDIA multi-monitor setups, and the brief black screens and window rearrangement suggest a display-server or driver issue rather than Blender alone. Try a current GNOME or KDE Plasma session, preferably under Wayland if your workflow supports it, and compare Blender there before changing lots of Blender settings.

Fedora made a noticeable difference for my own hardware compared with Mint. I would not treat that as proof that every Mint installation is slower, but testing Fedora or Kubuntu is a reasonable way to determine whether Cinnamon/X11 or the older software stack is responsible.